GCUH PAST PAPER 21-11-2021
فری تیاری کیلے وٹس ایپ
گروپ جوائن کریں
Click here
GCUH 5
years Past Papers Click
here
Show Answers
چار آپشن میں سے کسی ایک پر کلک کرنے سے جواب سرخ ہو جائے گا۔
ہائیڈروکلورک ایسڈ کا پی ایچ _____ ہے؟
Equal to 7
Less than 7
Greater than 7
All of these
اس سوال کو وضاحت کے ساتھ پڑھیں
Explanation
Hydrochloric acid (HCl) is a strong acid that completely dissociates in water, releasing H⁺ ions.
The pH scale ranges from 0 to 14 , where pH < 7 indicates acidity.
Since HCl increases H⁺ concentration, its pH is always less than 7 .
3
4
5
None of these
اس سوال کو وضاحت کے ساتھ پڑھیں
Explanation
Let's determine the number of significant figures in the number 2.3040 .
Rules for Significant Figures :
All non-zero digits are significant. Zeros between non-zero digits are significant. Leading zeros (zeros before the first non-zero digit) are not significant. Trailing zeros (zeros after the last non-zero digit) are significant if there is a decimal point. Now, analyze 2.3040:
The digits 2, 3, and 4 are non-zero and significant. The zero 0 between 3 and 4 is a trapped zero, so it is significant. The last zero 0 is a trailing zero and there is a decimal point, so it is significant. So, the significant digits are: 2, 3, 0, 4, 0 → that's 5 significant figures .
آلے کے غلط کام کرنے سے پیدا ہونے والی خرابی ______ ہے؟
Determinant Error
Systematic Error
Indeterminant
Both A and B
اس سوال کو وضاحت کے ساتھ پڑھیں
Explanation
Systematic errors are caused by faulty or improper functioning of instruments, or by a flaw in the experimental design.
These errors are consistent and repeatable, and can be identified and corrected.
متواتر جدول میں سونے کی علامت کیا ہے؟
Au
Ag
S
None of these
اس سوال کو وضاحت کے ساتھ پڑھیں
Explanation
Au comes from the Latin word aurum , meaning "gold" (from "glowing dawn") Atomic number: 79 Belongs to group 11 Category: transition metal Additional information:
Atomic mass: 196.97 u Melting point: 1,064°C Boiling point: 2,856°C Density : 19.3 g/cm³ (very heavy)
-1
0
1
None of these
اس سوال کو وضاحت کے ساتھ پڑھیں
Explanation
Let's evaluate the cross product step by step:
Given: i × ( j × k ) i × ( j × k )
Recall the vector triple product identity:
a × ( b × c ) = ( a ⋅ c ) b − ( a ⋅ b ) c a × ( b × c ) = ( a ⋅ c ) b − ( a ⋅ b ) c
Apply this with a = i a = i b = j b = j c = k c = k
i × ( j × k ) = ( i ⋅ k ) j − ( i ⋅ j ) k i × ( j × k ) = ( i ⋅ k ) j − ( i ⋅ j ) k
Now, compute the dot products:
So,
i × ( j × k ) = ( 0 ) j − ( 0 ) k = 0 i × ( j × k ) = ( 0 ) j − ( 0 ) k = 0
2
4
6
None of these
اس سوال کو وضاحت کے ساتھ پڑھیں
Explanation
To find the slope of the tangent to the curve y = x 2 y = x 2 ( 2 , 4 ) ( 2 , 4 ) y y x x
Differentiate y = x 2 y = x 2
d y d x = 2 x d x d y = 2 x Evaluate the derivative at x = 2 x = 2
d y d x ∣ x = 2 = 2 × 2 = 4 d x d y x = 2 = 2 × 2 = 4 Therefore, the slope of the tangent at ( 2 , 4 ) ( 2 , 4 ) is 4 4 .
9
6
2
None of these
اس سوال کو وضاحت کے ساتھ پڑھیں
Explanation
Let's evaluate the limit:
lim x → 3 x 2 − 9 x − 3 x → 3 lim x − 3 x 2 − 9
Step 1: Direct substitution gives 0 0 0 0
Notice that x 2 − 9 = ( x − 3 ) ( x + 3 ) x 2 − 9 = ( x − 3 ) ( x + 3 )
x 2 − 9 x − 3 = ( x − 3 ) ( x + 3 ) x − 3 = x + 3 (for x ≠ 3 ) x − 3 x 2 − 9 = x − 3 ( x − 3 ) ( x + 3 ) = x + 3 (for x = 3 )
Step 2: Now take the limit:
lim x → 3 ( x + 3 ) = 3 + 3 = 6 x → 3 lim ( x + 3 ) = 3 + 3 = 6
2/3
-3/2
-2/3
None of these
اس سوال کو وضاحت کے ساتھ پڑھیں
Explanation
Let's evaluate the definite integral:
∫ 0 1 ( 5 t 2 − 2 t ) d t ∫ 0 1 ( 5 t 2 − 2 t ) d t
Step 1: Find the antiderivative (indefinite integral):
∫ ( 5 t 2 − 2 t ) d t = 5 ⋅ t 3 3 − 2 ⋅ t 2 2 + C = 5 3 t 3 − t 2 + C ∫ ( 5 t 2 − 2 t ) d t = 5 ⋅ 3 t 3 − 2 ⋅ 2 t 2 + C = 3 5 t 3 − t 2 + C
Step 2: Evaluate from 0 to 1:
[ 5 3 t 3 − t 2 ] 0 1 = ( 5 3 ( 1 ) 3 − ( 1 ) 2 ) − ( 5 3 ( 0 ) 3 − ( 0 ) 2 ) = ( 5 3 − 1 ) − ( 0 ) = 5 3 − 3 3 = 2 3 [ 3 5 t 3 − t 2 ] 0 1 = ( 3 5 ( 1 ) 3 − ( 1 ) 2 ) − ( 3 5 ( 0 ) 3 − ( 0 ) 2 ) = ( 3 5 − 1 ) − ( 0 ) = 3 5 − 3 3 = 3 2
So, the value is 2 3 3 2 .
Bijective
Injective
Surjective
None of these
اس سوال کو وضاحت کے ساتھ پڑھیں
Explanation
The range of the function is equal to its codomain.
In this case, since the codomain is the set A, the condition "range = A" means the function is surjective .
5
7
3
None of these
اس سوال کو وضاحت کے ساتھ پڑھیں
Explanation
Let's evaluate f ( 2 ) f ( 2 ) f ( x ) = x 3 − x 2 + x + 1 f ( x ) = x 3 − x 2 + x + 1
Substitute x = 2 x = 2
f ( 2 ) = ( 2 ) 3 − ( 2 ) 2 + ( 2 ) + 1 f ( 2 ) = ( 2 ) 3 − ( 2 ) 2 + ( 2 ) + 1
Calculate step by step:
2 3 = 8 2 3 = 8
2 2 = 4 2 2 = 4
So, 8 − 4 = 4 8 − 4 = 4
Then, 4 + 2 = 6 4 + 2 = 6
Finally, 6 + 1 = 7 6 + 1 = 7
Therefore, f ( 2 ) = 7 f ( 2 ) = 7 .
